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Machining Powder Metallurgy (P/M) components have been regarded as one of the main issues due to its unique porous structure. Porosity can cause regional vibration and decrease tool life. It can also lower the standard of surface finish. Manufacturers and researchers have searched for different machining technique to overcome the difficulties, such as P/M densities, hardness or the free machining additive. The CVD deposition TiCN/Al2O3 coating cutting tool has been used in this experiment to search its improved capability in the P/M components machining. This paper will attempt to discuss the cutting force measurement, chip formation, and surface finish analysis. A general analysis of the machinability in the specific workpiece has been shown to compare the same machining condition by using different cutting tools.

The surface analysis is one of the most important factors of the metal machining process due to the tolerance and geometry requirements. The characteristic of powder metallurgy (P/M) surface geometry is the main issue here, because the porous structure affects the surface quality. A discontinuous cutting path and some vibration occur when cutting tool passes from the edge of one pore to that of another. The amorphous material such as Diamond-like carbon (DLC) coating has been applied on the cutting inserts to improve the machinability. This paper will evaluate the surface finish of the P/M components by employing a DLC cutting insert. Due to the specific physical properties of DLC coating, it is important to understand the effects of DLC coated insert on the surface roughness at different cutting speeds and feedrates. This work investigates the factors of friction between the cutting tools, workpiece and observes how the coating material affects the finish surface.

Powder metallurgy (P/M) industry has been known for the capability of producing near-net-shape parts. Its specific characteristics have resulted in lower production costs and eliminating many secondary machining. However, more and more P/M parts do require additional operations to fulfil their complex geometry features and surface roughness. Many of the machining factors that influence the machinability of cast and wrought steel parts, such as cutting speed, feedrate, coolant, tool geometry and shape, are also considered in the machining of P/M parts. However, composition, structure, and porosity of P/M are additional factors to be considered. Porosity in the P/M structure can decrease the machinability and shorten the tool life. Different variables have been considered in the material composition. Material densities and the free-machining additive manganese sulphide (MnS) are the two main factors of material composition, which dominate the machining performance.